1. Field of the Invention
The present invention relates to a power converter circuit having at least two controllable semiconductor components connected in parallel in the anode and cathode sides and having at least one control signal terminal.
2. Discussion of the Background
A semiconductor module as disclosed in DE 3 420 535 A1 operates as a chopper and has a plurality of field-effect transistors, in particular MOS-FETs, which are connected in parallel with one another, for a switching frequency of 20 kHz with switching times of about 100 ns for currents of 120 A, in which module a diode is electrically connected in parallel, via a backup capacitor, with each field-effect transistor, in the immediate vicinity thereof. The close routing in parallel results in a total inductance of only approximately 20 nH. At the same time, switching off 100 A in 100 ns results in an overvoltage of just 20 V.
What is disadvantageous in that case is that very high capacitor discharge currents are established given a defective field-effect transistor in the event of a short circuit, which currents may lead, via an arc, to destruction of the component and to explosion of the module.
DE 4 330 381 A1 discloses a protective circuit for an electrical circuit with a capacitor circuit, in which, in the case of a converter with a DC voltage intermediate circuit, in the event of the short circuit of an intermediate circuit capacitor, a reversible short-circuit current limiter prevents impermissibly high short-circuit currents in the DC voltage intermediate circuit and in the phase modules of the relevant power converter. This short-circuit current limiter has a PTC thermistor, which is connected in series, in a low-inductance and cooled manner, with at least one capacitor or with a capacitor bank of the DC voltage intermediate circuit. The PTC thermistor can be arranged in the DC voltage intermediate circuit or in the power converter. In parallel with the PTC thermistor, it is possible to connect a varistor and/or a non-reactive resistor and/or a diode reverse-biased in the direction of a short-circuit path, it being possible to combine the PTC thermistor and varistor or PTC thermistor and non-reactive resistor to form one component.
U.S. Pat. No. 4,583,146 discloses connecting a PTC thermistor and a varistor in parallel with a mechanical interrupter contact.
DE-A 2 831 495 discloses an overcurrent protection arrangement for an intermediate circuit converter or self-commutated invertor, in which a transistor is connected in series with the intermediate circuit capacitor, which transistor is in the on state during normal operation and is turned off in the event of a disturbance. A diode is reverse-connected in parallel with this transistor.
The production of a fuse by bonding is disclosed in DE 38 37 458 A1.